A known well tubular expansion system and method are disclosed in International patent application WO 2012/104257.
In this known method a well tubular is expanded by pulling an expansion cone therethrough.
A problem with this known method is that the expansion cone may get stuck in the partially expanded tubular. Downhole safety joints for releasing a drill string from a stuck Bore Hole Assembly are known from U.S. patent applications 2013/0319655 and 2003/0168859. These known safety joints are configured to collapse or release upon jarring and/or reverse rotation of the drill string in a direction opposite to the direction of rotation during normal drilling operations. The forces required for this collapse and/or release are still substantial to avoid inadvertent collapse and/or release during normal drilling operations.
There is a need for an improved low break out safety joint and method for releasably connecting a tubing expansion assembly to a drill string that is reliable and does not require large release forces.